brownlee



May 21, 1929.

D. T. BROWNLEE METHOD OF MAKING LOCK NUTS Filed July 31, 1926 INVENTOR:

Patented May 21, 1929.

PATENT OFFICE.

DALMAR T. BROWNLEE, OF INDIANAPOLIS, INDIANA.

METHOD OF MAKING LOCK NUTS.

Application filed July 31,

This invention relates to a novel method of producing a lock-nut of unitary construction with improved locking teeth, such as disclosed in my Patent No. 1,603,901, issued October 19, 1926 on application Serial No.

67,970, filed November 9, 1925.

This invention aims to provide a method for producing at low cost, a nut that is automatically and effectively locked when screwed into place, but is removable by means of a wrench on the application of considerable force.

Further aims and advantages of the inven tion appear hereinafter in connection with the accompanying drawings, wherein' Figure 1 is a plan view and Fig. 2 is a side elevation view of a partially completed nut, illustrative of one step in the method of production embodying the invention.

Fig. 3 is aplan view of a more nearly completed nut, illustrative of additional steps in the method of production.

Fig. 4 is a plan view and Fig. 5 is a side elevation View showing a completed nut, as preferably constructed.

In the drawings like reference characters in the different figures thereof indicate like parts or features herein referred to in detail.

Figs. 1 and 2 of the drawings are illustrative of the nut with the initial operations of boring, screw threading and forming completed. The nut shown has a body portion 1 of hexagon contour and an end portion 2 of cylindrical contour. The nut may be bored or punched and threaded in the usual manner, the thread in both port-ions being cut with a tap or threading tool in one con tinuous operation. An annular recess or undercut 3 of somewhat larger diameter than the outside diameter of the thread is cut in the hole of the end portion 2 where the latter adjoins the body portion 1. The recess divides the threads into two separate por tions 4; and 5, connected by an annular wall 6.

Fig. 3 is illustrative of the next succeeding operation which consists inv squeezing the cylindrical end portion 2 between hollow curved dies, thereby changing the plan contour of the end portion beyond the recess to an approximate ellipse, whose major axis is indicated by the line 7 7 and the minor axis by the line 88, or so that the threads are undulating.

A further operation consists in removing parts 9 and 10 (Fig. 3) of the elliptical end portion, preferably by milling, the milling 1926. Serial No. 126,227.

cutters being fed in laterally from opposite sides to approximately the curved lines 11 and 12, each of these lines intersecting the elliptical threaded surface at two points which are approximately at the intersections of said surface and the .maj or and minor axes as shown in Fig. This operation leaves parts 13 and 14 integral with thb body portions of the nut and with their arcuate inner threaded surfaces twisted with respect to the threads 5 of the body portion, as in Figs. 4 and 5, the resultant threads segment points 15 and 16 lying outside the inherent thread circle, and the segment points or teeth 17 and 18 lying within said circle, constituting elastic fingers having sharp anti-reverse locking teeth with a sufficient clearance angle that insures digging in should the nut start to unscrew on a coacting bolt.

If preferred the parts 9 and 10 may be removed by straddle milling with two parallel cutters or metal saws feeding across the end portion of the nut, in which case the lines 11 and 12 become straight lines but intersecting the elliptical threaded surface at the same points as before.

The material from which the nut is made is usually steel or wrought iron, and is finally heat treated or case-hardened in order that the anti-reverse teeth will be harder than the material of the bolt on which the nut is screwed.

While the drawings show a nut having a body portion of hexagon contour, it is obvious that the contour may be of other shape.

I claim:

1. The method of making screw-threaded lock-nuts which consists in pressing one end portion of a nut having screw-threaded hole radially to produce an undulating contour of the hole, and removing portions so as to produce screw thread segments on fingers shifted so that one end of the segment is within and the opposite end is without the inherent thread circle of the nut body.

2. The method of making a lock-nut from a screw-threaded nut which consists in deforming a portion of the screw thread so that the deformed thread in the nut extends across the normal thread circle, and in removing a portion of the deformed portion of the thread locate one end of the portion within and the opposite end outside the circle and afford a biting tooth clearance.

3. A method of making seren threaded. lock-nuts, characterized by producing on one end of a threaded nut body a deformed screw-thread portion bodily shifted so as to locate one end of the portion Within and the opposite end outside the inherent thread circle 01" the nut body, and removing portions only of the body at the ends of the deformed thread portion.

4. The method of making screw-threaded lock-nuts from threaded nuts having an end portion of cylindrical contour, by pressing the end portion to an approximately ellip tical contour with portions across the normal pitch circle and removing opposite parts thereof, and retaining the remaining parts of the elliptical portion to constitute anti-reverse members.

The method of making screw-threaded loek-nuts from threaded nuts having a body portion and a cylindrical end portion, by pressing the end portion to an iu'iproximately elliptical contour with thread portions across the normal pitch circle and removing opposite parts thereof, and retaining the other parts of the elliptical portion to form two opposite fingers ii'iteg'ral. With the body portion and, having deformed portions of scrow-threads to constitute anti-reverse teeth.

6. The method of making screw-threaded lock-nuts from threaded blanks having an end portion of cylindrical contour, consisting: in pressing the end portion from opposite sides so as to reduce its diameter in one direction and elongate its diameter in an other direction so that thread portions extend across the normal pitch circle, removing opposite parts thereof, and retaining tl e remaining parts of the end portion to constitute anti-reverse members.

7. The method of making screW-threaded lock-nuts from threaded blanks lnrving a body portion and cylindrical end portion and a counter-bore at a distance from the end and Within the cylindrical portion, consisting in changing the cylindrical. portion into an approximately elliptical contour so that detox-med thread portions extend across the normal pitch circle and removing opposite parts thereof, the parts of the elliptical portion rmmrininp: beingretained to constitute two opposite linpers inte 'ral with the body portion and relatively twisted from their initial positions and their deformed portiors o'l screw threads torming relieved cutting teeth adapted to dig into the threads oil: a enacting bolt should the nut start to unscrew.

8. The method of making sci-'e\v-tiu'eaded loclrnuts 't'rom threaded blanks having a body portion and a cylimlrical end portion by pressing the end portion to an approximately elliptical contour, and removing opposite parts thereof, retaining the remaining parts of the elliptical portion to constitute two opposite lingers integral with the body portion, so that the arcs oi" the portions of scrruv-lhreads in the lingers shall cross the normal pitch circle of the body portion screw-threads when the nut is viewed from the end.

9. The method of n'iaking' screw-threaded lock-nuts lromthreaded blanks having a body portion and a cylindrical end portion and a rounterbore at a distance from the end and Within the cylindrical portion, consisting in changing the cylindrical portion into an approximately elliptical contour, so as to produce deformed thread portions diagonally across the normal pitch circle, removing opposite parts thereof, and retaining the remaining parts of the elliptical portion to constitute two opposite lingers integral with the body portion and relatively twisted from their initial position, and their deformed portions of screwthreads forming anti-reverse teeth.

In testimony whereof, I affix my signature on the 30th day of July, 1926.

DALMAR T. BROW'NLEE. 

